Cardioplegia Practices in Elective Adult Coronary Artery Bypass Surgery: A National Survey

Duygu Durmaz1, Sedat Gündöner2, Hayrettin Tekümit1

1Department of Cardiothoracic and Vascular Surgery, Bandırma 17 Eylül University Faculty of Medicine, Balıkesir, Türkiye
2Department of Cardiothoracic and Vascular Surgery, Bandırma Training and Research Hospital, Balıkesir, Türkiye

Keywords: Cardioplegia; cabg; myocardial protection questionnaire.

Abstract

Objective: This study aimed to determine current cardioplegia practices in coronary artery bypass grafting surgery in Türkiye and variations according to the preferred cardioplegia type.

Methods: A 16-item questionnaire was distributed to members of the Turkish Society of Cardiovascular Surgery involved in adult cardiac surgery between November 2023 and February 2024. The questions addressed cardioplegia type, temperature, dose, delivery method, redosing interval, topical cooling, and hot-shot use.

Results: A total of 204 responses were analyzed. Blood cardioplegia was used by 69 (33.8%) participants, microplegia by 68 (33.3%), and Del Nido cardioplegia by 60 (29.4%). Most participants preferred a cardioplegia temperature of 4–10 °C (56.4%). Topical cardiac cooling was routinely used by 41.7%, and hot-shot administration by 47.1%. Antegrade cardioplegia alone was used by 59.3%, whereas 40.7% used combined antegrade and retrograde delivery. The roller pump was the most frequently preferred delivery technique (51.0%). The most common redosing interval was 15–20 minutes for blood cardioplegia (60.9%) and 60–90 minutes for Del Nido cardioplegia (71.7%). The most common blood-to-crystalloid ratios were 4:1 for blood cardioplegia (92.8%) and 1:4 for Del Nido cardioplegia (61.7%).

Conclusion: Cardioplegia practices in adult coronary artery bypass surgery vary considerably in Türkiye. Blood-based cardioplegia remains the predominant strategy. Further studies should investigate the associations between cardioplegia practices, myocardial protection markers, and postoperative outcomes.

Introduction

Advances in cardiac physiology and myocardial protection have played an important role in the development of cardiac surgery. Various practices and approaches have been developed to ensure optimal preservation of myocardial function and reserves. Cardioplegia is one of these approaches and is an essential component for the safe performing of procedures on the heart. Cardioplegia provides myocardial protection against ischemia-reperfusion injury during cardiac surgery and provides access to an immobilized and bloodless area through electromechanical arrest.[1]

At present, there are differences in the cardioplegia techniques used in myocardial protection. Potassium-based cold blood cardioplegia and Del Nido cardioplegia with 1:4 blood crystalloid mixture are extracellular cardioplegia and show a depolarizing effect. Intracellular cardioplegia types containing low sodium levels show their effects by hyperpolarization.[2] There is no standard in terms of optimal formula and delivery technique for cardioplegia.[3]

In this study, we conducted a survey to evaluate in detail the current cardioplegia practices in adult coronary artery bypass grafting (CABG) procedures in various cardiac surgery clinics in Türkiye.

Materials and Methods

We designed a descriptive cross-sectional study approved by the Non-Interventional Research Ethics Committee of Bandırma 17 Eylül University (Document Date and Number: 10.11.2023-553). Between December 2023 and February 2024, we conducted a 16-question survey sent to participants working in adult cardiac surgery in various centers in Türkiye and registered with the Turkish Society of Thoracic and Cardiovascular Surgery. The survey was created with the help of Google Forms (Google LLC, MountainView, CA) to cover common variations in cardioplegia applications in isolated coronary artery bypass surgery. The design of the survey was based on the cardioplegia study by Drury et al.[4] in the United Kingdom.The questions were developed through multiple iterations by cardiovascular surgical specialists. The technical functionality of the questionnaire was extensively tested before distribution.

Each participant was asked to provide demographic information and data on current cardioplegia practices in isolated CABG surgery, including the type of cardioplegia, initial dose, redosing interval, and delivery characteristics. Cardioplegia strategies were categorized according to their blood and crystalloid composition as conventional blood cardioplegia (blood diluted with crystalloid solution), microplegia (a predominantly whole-blood technique using concentrated cardioplegic agents with minimal crystalloid volume), Del Nido cardioplegia (blood mixed with Del Nido crystalloid solution), and crystalloid cardioplegia administered without added blood, including St. Thomas solution (Plegisol; Pfizer, New York, NY, USA) and Histidine-Tryptophan-Ketoglutarate (HTK) solution (Custodiol; Dr. Franz Köhler Chemie GmbH, Frankfurt, Germany). Exclusion criteria included incomplete questionnaires and multiple responses from the same internet protocol or email address. Identical responses from the same center were also excluded. Participant anonymity and confidentiality were ensured by design.

Responses were collected anonymously in Google Forms to protect participant identities from being seen. After all questionnaires were completed, responses were exported in Microsoft Excel format to IBM Statistical Package for the Social Sciences ver. 27.0 (IBM Corp., Armonk, NY, USA) for statistical analysis. Due to the nature of this research, most of the analyses performed were descriptive in nature. Categorical data were expressed as numbers and percentages. Multiple-choice items were represented by bar and pie charts. p<0.05 was considered statistically significant.

Results

Two hundred and forty-two responses were received. It was determined that 23 of these responses came from the same centers and contained the same answers, and 15 responses contained missing data. The remaining 204 responses were included in the final analysis. The most frequent responses were received from Education and Research Hospital (34.3%) and University Hospital (23.5%) (Table 1).

Table 1. Distribution of participants by institution type

Of the participants, 33.8% (n=69) reported using blood cardioplegia, 33.3% (n=68) microplegia, 29.4% (n=60) Del Nido cardioplegia, 2% (n=4) HTK cardioplegia, and 1.5% (n=3) St. Thomas cardioplegia (Fig. 1).

Figure 1. Preferred types of cardioplegia. HTK: Histidine–tryptophan–ketoglutarate.

The centers where the respondents work are shown in Table 1. Regardless of the type of cardioplegia, the most frequently preferred temperature value for cardioplegia temperature (n=115; 56.4%) was 4–10°. While 41.7% (n=85) of the participants preferred topical cooling of the heart, 30.4% (n=62) stated that they did not use topical cooling. While 47.1% (n=96) of the participants stated that they used hot-shot, 20.1% (n=41) stated that they did not. While 59.3% (n=121) of the participants preferred only an antegrade delivery route, 40.7% (n=83) reported using both an antegrade and retrograde delivery route. Among the participants, 51% (n=104) preferred roller pump and 49% (n=100) preferred pressure bag for cardioplegia delivery technique. The most preferred antegrade cardioplegia delivery pressure was 150–180 mmHg (30.9%; n=63), while the most preferred retrograde cardioplegia delivery pressure was 35–50 mmHg (63.2%; n=129) (Table 2).

Table 2. Participants’ responses regarding cardioplegia practices

When the participants were asked about the preferred time interval between doses of cardioplegia, the most common intervals were 15–20 min for blood cardioplegia (60.9%), 60–90 min for Del Nido cardioplegia (71.7%), and 15–20 min for microplegia (55.9%) (Table 3).

Table 3. Cardioplegia redosing intervals according to cardioplegia type

Regarding cardioplegia mixing ratios, all participants using microplegia reported using it undiluted (100.0%). The most common blood-to-crystalloid ratio was 4:1 for conventional blood cardioplegia (92.8%) and 1:4 for Del Nido cardioplegia (61.7%). All participants using St. Thomas and HTK solutions reported administering them without added blood (Table 4).

Table 4. Cardioplegia mixing ratios according to cardioplegia type

Participants’ induction dose preferences according to the type of cardioplegia used were found to be 10 mL/kg most frequently (39.1%) for blood cardioplegia, 10 mL/kg (45%) and 20 mL/kg (41.7%) for Del Nido cardioplegia, and 10 mL/kg most frequently (77.9%) for microplegia (Table 5).

Table 5. Initial cardioplegia dose according to cardioplegia type

Discussion

Cardiopulmonary bypass is widely used in cardiac surgery. Cardioplegia is an essential component of cardiac surgery procedures. Cardioplegia is necessary to eliminate global ischemia during aortic crossing and to achieve a bloodless and immobilized surgical field. There are various approaches associated with cardioplegia applications. Cardioplegia applications vary according to adult and pediatric patient profiles and may vary from institution to institution. Cardioplegia varies according to the composition, application methods, temperature and added substances; however, all available solutions contain potassium chloride (15–35 meq/L) to induce cardiac arrest.[5]

The use of single-dose cardioplegia in CABG procedures is becoming widespread. The benefits of single-dose cardioplegia include reduced aortic cross-clamp time, fewer intraoperative interruptions, and reduced incidence of post-operative myocardial dysfunction. Del Nido solution, originally developed for neonates and immature hearts, is one such cardioplegia and contains mannitol for cell membrane regulation, magnesium sulfate as a calcium channel blocker, sodium bicarbonate buffer, potassium chloride, and lidocaine as a sodium channel blocker. This solution is administered as 1:4 blood crystalloid.[6] St. Thomas cardioplegia is an extracellular crystalloid-based solution containing 16 mmol/L potassium and requiring repeat dosing for ~20 min.[6] Blood-based cardioplegia diluted with crystalloid in various ratios is frequently preferred because it provides a natural buffering system, normal oncotic pressure, improved oxygen delivery, and a natural free radical scavenging mechanism. Predominantly, 4:1 blood-crystalloid dilution is preferred.[7] Another solution defined as microplegia is a condensed version using whole blood cardioplegia. This solution offers all the advantages of blood cardioplegia without the potential disadvantages of hemodilution (such as myocardial edema).[8]

Crystalloid and blood-based cardioplegic solutions have been used together for many years for myocardial protection in cardiac surgery. However, the use of Del Nido cardioplegia solution, which can provide protection for up to 90 min in a single dose, has become popular in recent years.[9]

In our study, we determined that 33.8% of the participants preferred blood-based cardioplegia and 33.3% preferred microplegia. Del Nido cardioplegia (29.4%) was the most preferred solution after blood-based cardioplegia. Other solutions were HTK (2%) and St Thomas (1.5%).

Cold blood cardioplegia was first introduced in 1978,[10] and since then there has been ongoing debate about the optimal temperature for cardioplegic solutions. Cold cardioplegia has been used to maximise myocardial cooling and metabolic inhibition. However, some investigators recommend warm cardioplegia because it reduces the risks of membrane destabilization, intracellular edema, and the time required for rewarming of the heart.[11] In our study, 56.4% of the participants reported that they preferred a temperature of 4–10°C in cardioplegia solutions. However, 41.7% of the participants stated that they used topical cooling in addition to cardioplegia. In addition, 47.1% of the participants stated that they used Hot-Shot.

Retrograde coronary sinus perfusion is one of the techniques used to deliver cardioplegic solution during myocardial revascularization. It is unclear whether the combined antegrade/retrograde approach to myocardial protection provides significant clinical benefits. In a study comparing the efficacy of isolated antegrade and combined antegrade/retrograde approaches in CABG procedure, it was reported that postoperative cardiac output, electrophysiological and biochemical evidence of ischemia, need for temporary pacing and 30-day morbidity were similar between the groups.[12]

In our study, we found that the majority of the participants (59.3%) used the isolated antegrade cardioplegia method. Estimation of the pressure of the infusion during antegrade cardioplegia is based on measurement of the pressure at the initial part of the aorta. Aortic pressure is measured directly intraluminally using a pressure monitoring line attached to the cardioplegia cannula.[13] In our study, differences were determined between the participants’ responses to cardioplegia conduction pressure. According to the data we obtained, 30.9% of the participants stated that they preferred 150–180 mmHg pressure, 29.4% 120–150 mmHg pressure, 21.6% 180 mmHg pressure, and 18.1% 80–120 mmHg pressure. In addition, the most common (63.2%) retrograde cardioplegia pressure preferred by the participants was 35–50 mmHg.

In various centers, antegrade cardioplegia can be administered with the help of a roller pump from a heart-lung machine or with a manually squeezed pressure bag. In a study in which both techniques were compared, it was reported that cardioplegia given with a roller pump of the heart-lung machine and cardioplegia given with a pressure bag did not differ in terms of myocardial protection.[14] Another question of our study was by which method cardioplegia was administered. Of the participants who responded, 51% stated that cardioplegia was administered with the help of a heart-lung machine roller pump and 49% stated that cardioplegia was administered with a pressure bag.

During coronary artery surgery, redosing of cardioplegia is usually performed after each distal anastomosis, that is, every 10±5 min, but redosing intervals of 60 min have also been described. [15] However, the optimal redosing strategy of Del Nido cardioplegia is unclear. In our study, the participants who responded to the question about redosing frequently preferred intervals of 15–20 min for blood cardioplegia (60.9%), 15–20 min for microplegia (55.9%), and 60–90 min for Del Nido (71.7%).

Cardioplegia strategies can broadly be categorized as conventional blood cardioplegia consisting of blood diluted with crystalloid solution, microplegia using predominantly whole blood with minimal crystalloid volume, and crystalloid cardioplegia administered without added blood. Del Nido cardioplegia represents a blood–crystalloid strategy characterized by a higher crystalloid-to-blood ratio. In our study, the reported mixing ratios varied according to the cardioplegia strategy. Among participants using conventional blood cardioplegia, 92.8% reported a blood-to-crystalloid ratio of 4:1, whereas 61.7% of those using Del Nido cardioplegia reported a ratio of 1:4. All participants using microplegia reported using it undiluted (100.0%). Similarly, all participants using St. Thomas and HTK solutions reported administering these crystalloid solutions without added blood.

The strengths of this study include a high response rate and complete response rate from coronary artery surgery centers in Türkiye. However, limitations include the lack of a study evaluating the effectiveness of myocardial protection and the inability to determine whether the variety of responses given by the participants had an effect on patient outcomes.

Conclusion

This study on current cardioplegia practices in adult coronary artery surgery in Türkiye shows that there is heterogeneity in the cardioplegia approaches of the participants. We think that the main reason for this situation is the experience of surgeons in different ecoles. As shown in different studies,[16,17] most surgeons in our study used blood-based cardioplegia, while there are differences in the temperature of the solutions, delivery techniques, delivery routes and preferred delivery pressures. In the light of the data obtained in this study, we think that targeted, randomized studies designed to examine the effects of cardioplegia choices on clinical outcomes after cardiac surgery should be conducted.

Cite This Article: Durmaz D, Gündöner S, Tekümit H. Cardioplegia Practices in Elective Adult Coronary Artery Bypass Surgery: A National Survey. Koşuyolu Heart J 2026;29(3):175–180

Ethics Committee Approval

The study was approved by the Bandırma 17 Eylül University Non-Interventional Research Ethics Committee (no: 553, date: 10/11/2023).

Peer Review

Externally peer-reviewed.

Author Contributions

Concept – D.D., H.T., S.G.; Design – D.D., S.G.; Supervision – H.T., D.D.; Resource – S.G., D.D.; Materials – D.D., S.G.; Data collection and/or processing – S.G., D.D.; Data analysis and/or interpretation – S.G., D.D., H.T.; Literature search – D.D., S.G.; Writing – D.D., S.G., H.T.; Critical review – H.T., D.D., S.G.

Conflict of Interest

The authors have no conflicts of interest to declare.

Use for AI for Writing Assistance

No AI technologies utilized.

Financial Disclosure

The authors declared that this study received no financial support.

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Figure and Tables

Figure 1. Preferred types of cardioplegia. HTK: Histidine–tryptophan–ketoglutarate.
Table 1. Distribution of participants by institution type
Table 2. Participants’ responses regarding cardioplegia practices
Table 3. Cardioplegia redosing intervals according to cardioplegia type
Table 4. Cardioplegia mixing ratios according to cardioplegia type
Table 5. Initial cardioplegia dose according to cardioplegia type